The (free) Stuffit Expander is still quite useful, since it can unstuff Stuffit files (which you still very occasionally encounter) plus most other types of compression.

But Stuffit itself is pretty much dead. The built-in ZIP handling is more than enough for me, and those who need to make RAR and PAR type files can easily find inexpensive shareware that can do this for them (and then there are the aforementioned Terminal-accessible schemes).